How Action Mailer Works in Rails
  Sending emails in a rails application is very easy and quite handy using action mailer. First we will go through the basic setup of action mailer then we will go in details how it works.  Step 1    We can setup a mailer class using rails generator    rails generate mailer UserMailer   Step 2    Then we can create any instance method inside it.      def welcome_email(user)        @user = user        @url  = 'http://example.com/login'        mail(to: @user.email, subject: 'Welcome')      end   Step 3    We can call this method form model or controller or any kind of callbacks using     Like      UserMailer.welcome_email(@user).deliver   Step 4    You can set up a view template for the welcome_email in side the views/mailer directory    Like    welcome_email.html.erb    and you can specify the layout format here and can also access the instance variables defin...